How to Ferment Watermelon (11 Steps)

Lacto-fermentation happens when good bacteria interacts with the sugar in food in an oxygen-free environment, in this case pickling liquid. The process creates lactic acid, the compound responsible for tartness. Lacto-fermentation works with watermelons as well as it does other vegetables and fruits. Extra sugar from the watermelon juice puts lacto-fermentation into overdrive, taking the watermelon taste to a sweeter, tarter, more concentrated level. You can't heat watermelon juice, though, so make a couple adjustments to the basic pickling method.

Things You'll Need

  • Knife
  • Sieve
  • Bowl
  • Blender or food processor
  • Water
  • Kosher, pickling or sea salt
  • Pickling spices
  • Saucepan
  • Glass jars with lids
  • Cheesecloth or kitchen towel
  • Rubber band

Instructions

  1. Cut the watermelon into quarters. Cut the flesh from the rind and remove the seeds. Scrape all of the pink flesh clinging to the rind with a spoon.

  2. Peel the green skin from the watermelon rind and cut the rind into 1-inch pieces. Set it aside.

  3. Place the pink watermelon flesh in a blender or food processor and puree.

  4. Strain the pureed flesh through a cheesecloth-lined sieve into a bowl or container. Set the watermelon juice aside and discard the pulp.

  5. Mix water, salt and pickling spices in a saucepan. Use 3 tablespoons of kosher, pickling or sea salt for every 1/2 quart of water. Use a prepared pickling spice or create your own with a few antimicrobial spices, such as mustard seeds, cloves and bay leaf.

  6. Bring the pickling liquid to a boil and remove it from the heat. Let the liquid cool until warm.

  7. Pack the watermelon rind in a jar, leaving 1 to 2 inches of headspace.

  8. Pour an equal amount of watermelon juice into the cooled pickling liquid and stir. Pour the liquid into the jar until it reaches 1 inch from the top.

  9. Cover the mouth of the jar with a few layers of cheesecloth or a kitchen towel. Secure the towel with a rubber band.

  10. Set the watermelon pickles in a cool, dark area -- a cupboard works fine -- and let them ferment for one week. Taste the watermelon after a week and decide whether you want to continue fermenting or not. Taste the watermelon once a week until you're satisfied.

  11. Seal the jar with a lid and store the pickled rind in the refrigerator. Eat the pickled watermelon rind within one month.